You can compose a song even if you can’t play any instruments especially after 2000’s when writing melodies and lyrics on a pre-made track became a popular form of making music.

But it limits your creativity since you’re writing to a track you didn’t make. So learning an instrument and basic music theory enables you to create your own track which means there’s absolutely no limit to your creativity.

That’s why the Wonder Girls learned there instruments not only to perform on stage but to create there own musical color and it clearly shows on this album.